I am new to the development community and have started to learn about building Android from source. I've successfully built AOSP from source for my Nexus 6P (aosp_angler-userdebug, android-7.1.1_r14).
$make runs fine and I can install system.img and boot.img via fastboot and all is well.
However, the .zip made from
$make updatepackage fails when I try to flash it in TWPR, throwing an error
Failed to install, invalid zip file format!
After doing some research I noted that
$make updatepackage isn't producing a META-INF folder. When I run
$make dist, META-INF is created and I can then
$./build/tools/releasetools/ota_from_target_files.zip out/target/dist/ota_update.zip, but that ota_update.zip fails with the same error message in TWRP.